2000 Buick Regal Owner's Manual - Page 152

NOTICE: Do not attach anything like a temporary vehicle license or decal across the defogger grid. Ventilation System Adjust the direction of airflow by moving the vents. NOTICE: Don't use a razor blade or anything else sharp on the inside of the rear window. If you do, you could cut or damage the warming grid, and the repairs wouldn't be covered by your warranty. Your vehicle's flow-through ventilation system supplies outside air into the vehicle when it is moving. Outside air will also enter the vehicle when the air conditioning fan is running. If the airflow seems very low when the fan is adjusted to the highest setting regardless of the mode setting, your passenger compartment air filter may need to be replaced. See "Maintenance Schedule" or "Passenger Compartment Air Filter" in the Index. 3-9